Most sexually transmitted infections are caused by viruses or bacteria. STIs caused by viruses include herpes and genital warts, and the viruses that cause them aren’t even technically living organisms – they are pieces of genetic information that are able to infect a host cell. STIs caused by bacteria include gonorrhea and syphilis; bacteria are microscopic, single-celled organisms with relatively simple cell structures.
But some STIs are caused by other types of living organisms. Protozoan organisms are microscopic and unicellular, like bacteria; unlike bacteria, their cell structures more closely resemble that of the so-called “higher” life forms such as animals and plants. While protozoa are considered to be “animal-like,” they are not animals at all – they are single-celled organisms that reproduce asexually. When certain types of protozoans get into your body, they can cause infections – such as trichomoniasis, the most common curable STI among young females (as well as more females over 40 than previously thought). It is estimated that 7.4 million new cases of trichomoniasis occur annually in the United States; worldwide, there are about 170 million cases each year.
Trichomoniasis, colloquially known as trich, is spread by vaginal or anal intercourse, direct vulva-to-vulva contact, and other activities that involve passing secretions from one partner to another (e.g., sharing sex toys or mutual masturbation). Sexually active people can reduce the risk of contracting trichomoniasis by using latex barriers, such as condoms. Continue reading